1. Naphthalene, Ci0Hs, is present in a waste water sample at a concentration of
ID: 715196 • Letter: 1
Question
1. Naphthalene, Ci0Hs, is present in a waste water sample at a concentration of 71 ppm. Assuming the water sample density is 1.00 g/mL, what is the concentration of the Naphthalene in the sample, expressed in mM? When calculating molar mass of the naphthalene, don't forget to use the exact molar masses of the elements from the 5th edition Exploring Chemical Analysis periodic table. Prior editions have different values. Don't round the molar mass for significant figures. 2. How many mL of a concentrated salt solution, described below, should be used to obtain 316 mL of 0.255 Molar salt solution? Concentrated salt solution information: Weight pecent solute Molar Mass solute (grams /mole) Density of salt solution (grams soluton/mL solution) 1.461 42.1 168.36 The concentration of a hypothetical molecule, A B&Ca,is 978 mg/dl. masses of the hypothetical elements are in the table below. What is the molarity of this molecule in the solution? 3. The molar Molar Mass Element (grams/mole) 12.026 18484 14.811 4. The US Institute of Medicine Food and Nutritin Board recommends a daily intake of 0.050 mg Fluoride per kg of body mg F Kg body weight 0.050 weight ( health. Many municipalities add fluoride ion to the water supply to assure that everybody gets their daily fluoride dose. How many Liters of water having 34 HM NaE should a 143 pound person consume per day to meet this recommendation? ) to maintain dental Assume full dissociation of the fluoride ion. 5. A tasty crunchy salty snack, packaged up in a 6.00 oz serving, contains 28.3% fat, 41.7% carbohydrate, and 15.3% protein. How many kCal are in an entire 6oz salty savory serving?fat is 9.00 Calgram carbohydrate is 4.00 kCal/gram protein is 4.00 kCal/gramExplanation / Answer
Answer 1:
Molar Mass of Naphthalene = 128.1705g/mol
Density of waste water= 1 g/ml = mass/ volume
mass of waste water = 1*0.001 = 0.001g
molar Mass of water = 18
molarity = 71ppm
Molarity = (weight/molar mass)/volume
volume = 0.782 liters
mass of napthalene = Molarity x Molar Mass of napthalene = 0.000071 X 128.1705 = 0.0091
Molarity of napthalene = (weight/molar mass)/volume
= ( 0.0091 /128.1705)/0.782
= 9.079 X10-5 Mole
= 0.09mM
Answer 2:
Given that-
weight of the salt solution = 42.1
Molar mass of the salt solution = 168.36
The density of the salt solution = 1.461
From this information, we can calculate the molarity M1 of the salt solution
Density = mass/ volume
volume = mass /density = 42.1/1.461 =28.835mL
Molarity = (weight /molar maas)/volume in liters
= (42.1/168.36)/0.0288
= 8.682M
now applying the formula M1V1= M2V2
8.682 x V1 = 0.255 X 316mL
V1 = 9.281mL
therfore 9.281mL of concentrated salt solution volume has to be taken to obtain the required volume of concentration.
Answer 3:
given the concentration as 978mg/dL which means 978mg in 1liter that is 0.978g in 1liter.
the compound is A4B6C2, so we can calculate the molar mass which is =88.8164
now we can calculate the molarity:
Molarity = (weight/molar mass)/volumes in liters
= (0.978/88.8164)/1
= 0.01M
Answer 4:
Given that 0.050mg of F ion in per kg body weight
therefore in 143 pounds, that is 64.8637Kg the required amount of fluorine will be 3.243185mg (64.8637*0.050)
Molarity = (weight/Molar mass)/volume
molar mass of NaF = 41.98817
3.4 X10-5 = (3.243185/41.98817)/Volume
volume = 2.27 liters
Answer 5 :
Given 6 oz serving which means 170grams
now in this 28.3% is fat that is 48.11 grams
and the fat is 9 Kcal/grams so in 48.11gm fat there will 432.299 Kcal.
Similarly, Carbohydrate is present 41.7% that is 70.89 grams
and the Carbohydrate is 4 Kcal/grams so in 70.89gm carbohydrate, there will 283.56 Kcal.
Similarly, Protein is present 15.3% that is 26.01 grams
and the Protein is 4 Kcal/grams so, in 26.01gm carbohydrate, there will 104.04 Kcal.
therefore in total the Kcal = 432.299 + 283.56 +104.04 = 819.899Kcal.
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